As a worldwide array of 3000 floats, Argo data is unique for several reasons:

• The distribution of data throughout the oceans is uniform rather than dependent on shipping lines.
• There is a of lack of seasonal bias since the floats operate year round.
• An efficient data management network that provides free automatic quality controlled data within 24 hours and scientifically quality controlled, delayed mode data within several months.
• Multi-national collaboration to deploy, monitor and analyze floats and their data.

The following table summarizes some novel parts of Argo's data set:

Observation type	T/S	Number per year	Max Depth	Geographical restriction
Ship-based temperature and salinity	T + S	5000 (to 1000m)	Full water depth	• Limited by ship endurance (100 per month) • Few at high latitude in winter • Typically along lines
Expendable XBT from merchant ships	T	25,000	750m	• Along shipping routes • Avoid high latitude in winter • Many areas unsampled
Argo	T + S	42,000 (May 2004) 100,000 (2006)	2000m	• Ice free areas deeper than 2000m

Argo Floats

Global coverage at the target of 3° x 3° density should be achieved around the end of 2006.

Ship Based CTDs during WOCE

In 8 years the WOCE Hydrographic survey collected data from about 30,000 CTD stations mostly along the sections shown here.

Ship based XBTs

Positions of XBT temperature profiles from merchant ships in 2002. Note poor coverage in southern hemisphere.